Liquid crystal display

ABSTRACT

A liquid crystal display according to the present invention includes a first substrate and a second substrate facing each other, a pixel electrode disposed on the first substrate and including a first sub-pixel electrode and a second sub-pixel electrode spaced apart from the first sub-pixel electrode by a gap, a common electrode disposed on the second substrate, a shielding member disposed on the first substrate or the second substrate and overlapping the gap between the first sub-pixel electrode and the second sub-pixel electrode, an alignment layer disposed on at least one of the pixel electrode and the common electrode, and a liquid crystal layer disposed between the first substrate and the second substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2008-0008999, filed on Jan. 29, 2008, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display.

2. Discussion of the Background

Liquid crystal displays (LCDs) are one of the most widely used flatpanel displays, and an LCD includes a pair of panels provided withfield-generating electrodes, such as pixel electrodes and a commonelectrode, and a liquid crystal (LC) layer disposed between the twopanels. The LCD displays images when voltages are applied to thefield-generating electrodes to generate an electric field in the LClayer that determines the orientations of LC molecules therein to adjustpolarization of incident light.

In a vertical alignment (VA) mode LCD, the longitudinal axes of the LCmolecules are perpendicular to the upper and lower panels in the absenceof an electric field, and thus, the contrast ratio may be large and thereference viewing angle may be wide.

In the VA mode LCD, to obtain a wide viewing angle, a plurality ofdomains in which the alignment directions of the LC molecules aredifferent from each other, may be formed in one pixel.

To achieve this, at least one cutout may be formed in at least one fieldgenerating electrode. In this method, the plurality of domains may beformed by aligning the LC molecules vertically with respect to thefringe field generated between the edges of the cutout and the fieldgenerating electrodes facing the edges.

However, the aperture ratio may be decreased in this structure. Also,the LC molecules disposed near the cutouts may be easily alignedvertically with respect to the fringe field, but the LC moleculesdisposed in the central portions of the domains, which are far from thecutouts, may generate a random motion such that the response speedbecomes slow and a domain of the reverse direction is formed, which maycause an instant afterimage to appear.

Alternatively, the alignment direction of the LC molecules and thealignment angle may be controlled by irradiating light onto thealignment layer. In this light alignment method, it may not be necessaryto form the cutouts in the field generating electrodes, so the apertureratio may be increased and the response time of the LC molecules may beimproved by a pretilt angle generated during the light alignment.

On the other hand, the VA mode LCD may have lower side visibility thanfront visibility, and to solve this problem, it has been suggested thatone pixel be divided into two subpixels and different voltages beapplied to the subpixels.

However, when the light alignment method is adapted to a structurehaving two subpixels, the alignment direction of LC molecules subjectedto the light alignment may be different from the alignment direction ofthe LC molecules generated by the fringe field in a gap between twosubpixels of the LCD so that texture may be generated in thecorresponding portion. The texture may decrease transmittance and appearas a stain such that the display characteristics may be deteriorated.

SUMMARY OF THE INVENTION

The present invention provides a liquid crystal display (LCD) in whichone pixel is divided into two subpixels, and the generation of texturedue to a light alignment method may be reduced.

Additional features of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention.

The present invention discloses an LCD including a first substrate and asecond substrate facing each other, a pixel electrode disposed on thefirst substrate and including a first sub-pixel electrode and a secondsub-pixel electrode spaced apart from the first sub-pixel electrode by agap, a common electrode disposed on the second substrate, a shieldingmember disposed on the first substrate or the second substrate andoverlapping the gap between the first sub-pixel electrode and the secondsub-pixel electrode, an alignment layer disposed on at least one of thepixel electrode and the common electrode, and a liquid crystal (LC)layer disposed between the first substrate and the second substrate.

The present invention also discloses an LCD including a pixel electrodeincluding a first sub-pixel electrode and a second sub-pixel electrode,a common electrode facing the pixel electrode, a first LC layer disposedbetween the first sub-pixel electrode and the common electrode, a secondLC layer disposed between the second sub-pixel electrode and the commonelectrode, and a shielding member disposed under the pixel electrode orunder the common electrode and overlapping a gap between the firstsub-pixel electrode and the second sub-pixel electrode. The first LClayer includes a plurality of domains where liquid crystal molecules arealigned in a left-upper direction, a left-lower direction, a right-upperdirection, and a right-lower direction, respectively, and the second LClayer includes a plurality of domains aligned in the left-upperdirection, the left-lower direction, the right-upper direction, and theright-lower direction, respectively.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is an equivalent circuit diagram of a pixel of an LCD accordingto an exemplary embodiment of the present invention.

FIG. 2 is a layout view of an LCD according to an exemplary embodimentof the present invention.

FIG. 3 and FIG. 4 are layout views respectively showing a pixelelectrode and a gate conductor in the LCD shown in FIG. 2.

FIG. 5 is a cross-sectional view of the LCD taken along line V-V of FIG.2.

FIG. 6 is a layout view of an LCD according to another exemplaryembodiment of the present invention.

FIG. 7 and FIG. 8 are layout views respectively showing a pixelelectrode and a gate conductor in the LCD of FIG. 6.

FIG. 9 is a layout view showing a pixel electrode, a gate conductor, andthe alignment direction of LC molecules of FIG. 6.

FIG. 10 is a layout view of an LCD according to another exemplaryembodiment of the present invention.

FIG. 11 is a schematic diagram showing a pixel electrode and a shieldingmember in the LCD of FIG. 10.

FIG. 12 is a cross-sectional view of the LCD taken along line XII-XII ofFIG. 10.

FIG. 13 is a layout view of an LCD according to another exemplaryembodiment of the present invention.

FIG. 14 is a schematic diagram showing two masks under light alignment.

FIG. 15 is a schematic diagram showing a method for irradiating lightusing the masks shown in FIG. 14.

FIG. 16 and FIG. 17 are schematic diagrams showing the alignment of LCmolecules subjected to the light alignment method.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which embodiments of the invention are shown.This invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure isthorough, and will fully convey the scope of the invention to thoseskilled in the art. In the drawings, the size and relative sizes oflayers and regions may be exaggerated for clarity. Like referencenumerals in the drawings denote like elements.

It will be understood that when an element or layer is referred to asbeing “on” or “connected to” another element or layer, it can bedirectly on or directly connected to the other element or layer, orintervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on” or “directly connected to”another element or layer, there are no intervening elements or layerspresent.

Exemplary Embodiment 1

An LCD according to an exemplary embodiment of the present inventionwill be described in detail below with reference to FIG. 1, FIG. 2, FIG.3, FIG. 4, and FIG. 5.

FIG. 1 is an equivalent circuit diagram of one pixel of an LCD accordingto an exemplary embodiment of the present invention, FIG. 2 is a layoutview of an LCD according to an exemplary embodiment of the presentinvention, FIG. 3 and FIG. 4 are layout views respectively showing apixel electrode and a gate conductor in the LCD of FIG. 2, and FIG. 5 isa cross-sectional view taken along line V-V of FIG. 2.

Referring to FIG. 1, each pixel PX includes a pair of subpixels PXa andPXb, and each subpixel PXa and PXb includes a switching element Qa andQb connected to a gate line 121 and a corresponding data line 171 a and171 b, a LC capacitor Clca and Clcb connected to the switching elementQa and Qb, and a storage capacitor Csta and Cstb connected to theswitching element Qa and Qb and a storage electrode line 131.

Each switching element Qa and Qb may be a three terminal elementincluding a control terminal, an input terminal, and an output terminal.The control terminal thereof is connected to the gate line 121, and theinput terminal is connected to the corresponding data line 171 a and 171b, and the output terminal is connected to the LC capacitor Clca andClcb and the storage capacitor Csta and Cstb.

The storage capacitors Csta and Cstb, which serve as auxiliaries to theLC capacitors Clca and Clcb, are formed where the storage electrode line131 and the pixel electrode (not shown) overlap each other with aninsulator disposed therebetween, and a set voltage, such as a commonvoltage Vcom or the like, is applied to the storage electrode line 131.Also, the storage capacitors Csta and Cstb may be formed where the pixelelectrode overlaps the immediately previous gate line with an insulatordisposed therebetween.

Referring to FIG. 2, FIG. 3, FIG. 4, and FIG. 5, an LCD according to thepresent exemplary embodiment includes a thin film transistor array panel100 and a common electrode panel 200, and an LC layer 3 disposedtherebetween.

First, the thin film transistor array panel 100 will be described.

A gate conductor including a plurality of gate lines 121 and a pluralityof storage electrode lines 131 are disposed on an insulation substrate110.

The gate lines 121 transfer gate signals and extend mainly in ahorizontal direction. Each gate line 121 includes a plurality of firstand second gate electrodes 124 a and 124 b, which protrude upward, and awide end portion 129.

The storage electrode lines 131 transfer a common voltage and extendmainly in a horizontal direction. Each storage electrode line 131 isdisposed between two gate lines 121 and includes a plurality of storageelectrodes 133.

Referring to FIG. 2 and FIG. 4, each storage electrode 133 may have aloop shape including upper, lower, right, and left portions. The upperportion of the storage electrode 133 includes expansions 134 a and 134 bthat extend upward and downward, respectively, and are connected to eachother. The lower portion of the storage electrode 133 includesexpansions 135 a and 135 b that extend upward and downward,respectively, and are not connected to each other. A portion of thestorage electrode 133 having the loop shape between the expansions 135 aand 135 b is removed. The upper and lower portions of the storageelectrode 133 are wider than the right and left portions.

A gate insulating layer 140 is disposed on the gate line 121 and thestorage electrode line 131.

A pair of first and second semiconductor stripes (not shown) aredisposed on the gate insulating layer 140. The first and secondsemiconductor stripes extend mainly in a vertical direction. The firstsemiconductor stripe includes a first protrusion 154 a protruding towardthe first gate electrode 124 a, and the second semiconductor stripeincludes a second protrusion 154 b protruding toward the second gateelectrode 124 b.

Ohmic contact stripes (not shown), first ohmic contact islands 165 a,and second ohmic contact islands (not shown) are disposed on thesemiconductor stripe. An ohmic contact stripe includes first protrusions163 a and second protrusions (not shown), and a first protrusion 163 aand a first ohmic contact island 165 a are disposed as a pair and faceeach other on a first protrusion 154 a of the semiconductor stripe, anda second protrusion and a second ohmic contact island are disposed as apair and face each other on a protrusion 154 b of the semiconductorstripe.

First and second data lines 171 a and 171 b and first and second drainelectrodes 175 a and 175 b are disposed on the ohmic contact stripe andthe gate insulating layer 140.

The first and second data lines 171 a and 171 b extend in a verticaldirection, thereby crossing the gate lines 121 and storage electrodelines 131, and transmit data voltages. The first data line 171 aincludes first source electrodes 173 a extending toward the first gateelectrodes 124 a and an end portion 179 a having a wide area. The seconddata line 171 b include second source electrodes 173 b extending towardthe second gate electrodes 124 b and an end portion 179 b having a widearea. The first data line 171 a and the second data line 171 b mayreceive different voltages.

The first drain electrode 175 a is opposite to the first sourceelectrode 173 a with respect to the first gate electrode 124 a, and thesecond drain electrode 175 b is opposite to the second source electrode173 b with respect to the second gate electrode 124 b. The end portionsof the first and second drain electrodes 175 a and 175 b are partiallyenclosed by the curved portion of the first and second source electrodes173 a and 173 b.

The semiconductor stripe may have substantially the same plane shape asthe first and second data lines 171 a and 171 b and the first and seconddrain electrodes 175 a and 175 b except for the channel regions betweenthe first source electrode 173 a and the first drain electrode 175 a andthe channel region between the second source electrode 173 b and thesecond drain electrode 175 b.

The ohmic contact stripe is disposed between the semiconductor stripeand the first and second data lines 171 a and 171 b, and may havesubstantially the same plane shape as the first and second data lines171 a and 171 b. The first and second ohmic contact islands are disposedbetween the semiconductor stripe and the first and second drainelectrodes 175 a and 175 b, and have substantially the same plane shapeas the first and second drain electrodes 175 a and 175 b.

A blocking layer 160, which may be made of an inorganic insulatingmaterial such as silicon nitride (SiN_(x)) or silicon oxide (SiO₂), isdisposed on the first and second data lines 171 a and 171 b and thefirst and second drain electrodes 175 a and 175 b, and a color filter230 is disposed thereon.

The color filter 230 may be a red filter, a green filter, or a bluefilter that extends in a direction parallel to the first and second datalines 171 a and 171 b along the pixels in a column. Pixels having redfilters, pixels having green filters, and pixels having blue filters maybe alternately arranged.

The color filter 230 includes a plurality of openings 234 a, 234 b, 235a, and 235 b. The openings 234 a, 234 b, 235 a, and 235 b overlap theexpansions 134 a, 134 b, 135 a, and 135 b, respectively, of the storageelectrode 133.

A passivation layer 180 is disposed on the color filter 230. Thepassivation layer 180 may be made of an inorganic insulating material,such as silicon nitride or silicon oxide, which may prevent the colorfilter 230 from lifting and may prevent a chemical solution, such as anetchant, from flowing into the color filter 230.

The passivation layer 180, the color filter 230, and the blocking layer160 have a plurality of contact holes 185 a and 185 b respectivelyexposing the first and second drain electrodes 175 a and 175 b, and thepassivation layer 180 and the blocking layer 160 have a plurality ofcontact holes 182 a and 182 b respectively exposing the end portions 179a and 179 b of the first and second data lines 171 a and 171 b. Thepassivation layer 180, the blocking layer 160, and the gate insulatinglayer 140 have a plurality of contact holes 181 respectively exposingthe end portions 129 of the gate lines 121.

A pixel electrode 191 and a plurality of contact assistants 81, 82 a,and 82 b are disposed on the passivation layer 180.

The pixel electrode 191 includes a pair of first and second sub-pixelelectrodes 191 a and 191 b that are spaced apart from each other with agap 91 therebetween. As shown FIG. 2 and FIG. 3, the first sub-pixelelectrode 191 a may have a quadrangular shape, and the second sub-pixelelectrode 191 b encloses the first sub-pixel electrode 191 a with thegap 91 therebetween.

The gap 91 between the first sub-pixel electrode 191 a and the secondsub-pixel electrode 191 b may have a quadrangular loop shape, and theabove-described storage electrode 133 having a quadrangular loop shapeoverlaps the gap 91 and functions as a shielding member to block lightleakage between the first sub-pixel electrode 191 a and the secondsub-pixel electrode 191 b.

Also, the expansions 134 a, 134 b, 135 a, and 135 b of the storageelectrode 133 function as shielding members to cover the texture causedby the light alignment, which will be described in detail below.

Further, the expansions 134 a, 135 a, 134 b, and 135 b of the storageelectrode 133 overlap the first sub-pixel electrode 191 a or the secondsub-pixel electrode 191 b to form a storage capacitor Cst.

That is to say, the first sub-pixel electrode 191 a overlaps theexpansions 134 a and 135 a of the storage electrode 133 to form thestorage capacitor Csta. The openings 234 a and 235 a of the color filter230 are disposed where the first sub-pixel electrode 191 a and theexpansions 134 a and 135 a of the storage electrode 133 overlap eachother so that the thickness of the insulator of the storage capacitorCsta may be reduced, which may increase the storage capacitance.

The second sub-pixel electrode 191 b overlaps the expansions 134 b and135 b of the storage electrode 133 to form the storage capacitor Cstb.The openings 234 b and 235 b of the color filter 230 are disposed wherethe second sub-pixel electrode 191 b and the expansions 134 b and 135 bof the storage electrode 133 overlap each other so that the thickness ofthe insulator of the storage capacitor Cstb may be reduced, which mayincrease the storage capacitance.

A first gate electrode 124 a, a first protrusion 154 a of thesemiconductor stripe, a first source electrode 173 a, and a first drainelectrode 175 a form a first thin film transistor Qa, and the first thinfilm transistor Qa is connected to the first sub-pixel electrode 191 avia the contact hole 185 a. A second gate electrode 124 b, a secondprotrusion 154 b of the semiconductor stripe, a second source electrode173 b, and a second drain electrode 175 b form a second thin filmtransistor Qb, and the second thin film transistor Qb is connected tothe second sub-pixel electrode 191 b via the contact hole 185 b.

In this way, the first sub-pixel electrode 191 a and the secondsub-pixel electrode 191 b that form one pixel electrode 191 arerespectively connected to the first thin film transistor Qa and to thesecond thin film transistor Qb so that the first and second sub-pixelelectrodes 191 a and 191 b receive different data voltages through thefirst and second data lines 171 a and 171 b, respectively.Alternatively, the first and second sub-pixel electrodes 191 a and 191 bmay receive separate data voltages through one data line at differenttimes, or only the first sub-pixel electrode 191 a may be connected tothe thin film transistor while the second sub-pixel electrode 191 b iscapacitively coupled to the first sub-pixel electrode 191 a so that onlythe first sub-pixel electrode 191 a receives the data voltage and thesecond sub-pixel electrode 191 b may have a changing voltage accordingto the change of a voltage of the first sub-pixel electrode 191 a.

In this case, the area ratio of the first sub-pixel electrode 191 a andthe second sub-pixel electrode 19 b deviates from about 1:1, and thesecond sub-pixel electrode 191 b is larger than the first sub-pixelelectrode 191 a. The area ratio of the first sub-pixel electrode 191 aand the second sub-pixel electrode 191 b may be adjusted by regulatingthe height of the first sub-pixel electrode 191 a. Here, the voltage ofthe first sub-pixel electrode 191 a having a relatively small area ishigher than the voltage of the second sub-pixel electrode 191 b havingthe relatively large area.

In this way, since the voltages of the first sub-pixel electrode 191 aand the second sub-pixel electrode 191 b are different from each other,the voltages applied to the first LC capacitor Clca between the firstsub-pixel electrode 191 a and the common electrode 270 and the second LCcapacitor Clcb between the second sub-pixel electrode 191 b and thecommon electrode 270 differ from each other so that the tilt angle ofthe LC molecules in the first subpixel and the second subpixel differfrom each other. As a result, the luminance of the two subpixels differsfrom each other. Accordingly, by adjusting the voltages of the first andsecond LC capacitors Clca and Clcb appropriately, the images shown atthe side of the display may be approximate to the image shown at thefront, that is to say, the gamma curve at the side of the display may beapproximately close to the gamma curve at the front, thereby improvingthe side visibility.

The contact assistants 81, 82 a, and 82 b are connected with the endportion 129 of the gate line 121 and with the end portions 179 a and 179b of the data lines 171 a, 171 b via the contact holes 181, 182 a, and182 b, respectively. The contact assistants 81, 82 a, and 82 bcomplement adhesion of the end portion 129 of the gate line 121 and theend portions 179 a and 179 b of the data line 171 a and 171 b with anexternal device, such as a driver IC, and protect the end portions 129,179 a, and 179 b.

Next, the structure of the common electrode panel 200 will be described.

A light blocking member 220 is disposed on an insulating substrate 210,an overcoat 250 is disposed on the light blocking member 220, and acommon electrode 270 is disposed on the overcoat 250.

Alignment layers 11 and 21 are respectively disposed on the facingsurfaces of the thin film transistor array panel 100 and the commonelectrode panel 200. The alignment layers 11 and 21 are verticalalignment layers, and the surfaces of the alignment layers have endportions that are slanted in different directions according to regions.

An LC layer 3 is disposed between the thin film transistor array panel100 and the common electrode panel 200. The LC layer 3 includes aplurality of LC molecules 310 having negative dielectric anisotropy.

Referring to FIG. 2 and FIG. 3, the part of the LC layer 3 disposedbetween the first sub-pixel electrode 191 a and the common electrode 270is referred to as a first LC layer and the part of the LC layer disposedbetween the second sub-pixel electrode 191 b and the common electrode270 is referred to as a second LC layer. The LC molecules 310 of thefirst LC layer and the second LC layer are aligned in four differentdirections as shown by the arrows. That is to say, each sub-pixel mayinclude four domains having different alignment directions of the LCmolecules, such as the left-upper direction, the left-lower direction,the right-upper direction, and the right-lower direction. Here, the tailof the arrow represents the long axis direction of the LC molecule 310prior to alignment, that is to say, the vertical direction with therespect to the substrate, and the head of the arrow represents thealignment direction of the LC molecule 310. However, the number of thealignment directions of the LC molecules 310 may be three or less orfive or more, if necessary.

Such domains may be formed by the light alignment method in which thelight is irradiated onto the alignment layers 11 and 21. In the lightalignment method, the light is obliquely irradiated onto the verticalalignment layer to align the light reactivity chains formed on thesurfaces of the alignment layer surface in the direction of lightirradiation, and when the light is obliquely irradiated in variousdirections, a plurality of domains may be formed.

Next, the light alignment method will be described with reference toFIG. 14, FIG. 15, FIG. 16, and FIG. 17.

FIG. 14 is a schematic diagram showing two masks under light alignment,FIG. 15 is a schematic diagram showing a method for irradiating light byusing the masks shown in FIG. 14, and FIG. 16 and FIG. 17 are schematicdiagrams showing the alignment of LC molecules subjected to the lightalignment method.

Referring to FIG. 14, a mask used under the light alignment may be afirst mask 10 including a plurality of openings 10 a parallel to the tothe long edge of the substrate, or a second mask 20 including aplurality of openings 20 a perpendicular to the long edge of thesubstrate.

Referring to FIG. 14( a) and FIG. 15( a), the first mask 10 is alignedon the thin film transistor array panel 100 coated with the alignmentlayer 11, and light, such as ultraviolet (UV) rays, is irradiated at anoblique angle to execute a first exposure. Next, the ultraviolet (UV)rays are obliquely irradiated in the direction opposite to the directionof the first exposure to execute a second exposure.

Here, the light irradiation is executed by moving along the directionparallel to the long axis of the openings 10 a of the mask 10, that isto say, the upper and lower directions (arrow directions) in FIG. 14(a). When the light irradiation is not executed by moving along thedirection parallel to the long axis of the openings 10 a, the regionthat is practically exposed may be reduced due to light diffraction, andalso the process margin for the distance between the substrate and themask and the exposing angle may be decreased. The method in which thelight is obliquely irradiated onto the surface of the alignment layermay be performed by altering the angle of the substrate or the devicefor irradiating light.

For example, the left half portion of the pixel area may be irradiatedby light having a declination angle from the lower side toward the upperside, and the right half portion of the pixel area may be irradiated bylight having a declination angle from the upper side toward the lowerside. Accordingly, as shown in FIG. 16( a) and FIG. 17( a), two regionshaving opposite tilt directions of LC molecules may be formed.

Similarly, referring to FIG. 14( b) and FIG. 15( b), the second mask 20is aligned on the common electrode panel 200 coated with the alignmentlayer 21, and light, such as UV rays, is irradiated at an oblique angleto execute a third exposure. Next, the UV rays are obliquely irradiatedin the direction opposite to the direction of the third exposure toexecute a fourth exposure.

Here, the light irradiation is executed by moving along the directionparallel to the long axis of the openings 20 a of the mask 20, that isto say, the right and left directions (arrow directions) in FIG. 14( b).For example, the upper half portion of the pixel area may be irradiatedby light having a declination angle from the left side toward the rightside, and the lower half portion of the pixel area may be irradiated bylight having a declination angle from the right side toward the leftside, and accordingly, as shown in FIG. 16( b), two regions havingopposite tilt directions of LC molecules may be formed. Alternatively,the upper half portion of the pixel area may be irradiated by lighthaving a declination angle from the right side toward the left side, andthe lower half portion of the pixel area may be irradiated by lighthaving a declination direction from the left side toward the right side,and accordingly, as shown in FIG. 17( b), two regions having oppositetilt directions of LC molecules may be formed.

In this way, the same effect of rubbing the surface of the alignmentlayer in a uniform direction may be obtained by obliquely irradiatinglight with respect to the surface of the alignment layer. That is, thealignment direction of the surface of the alignment layer is decidedaccording to the direction of light irradiation, so that a plurality ofdomains having various pre-tilt directions of the LC molecules may beformed by dividing one pixel into a plurality of regions and performinglight exposure thereon.

Referring to FIG. 16 and FIG. 17, when assembling the thin filmtransistor array panel 100 having a left half portion and a right halfportion that are irradiated in opposite directions to each other and thecommon electrode panel 200 having an upper half portion and a lower halfportion that are irradiated in opposite directions to each other, asshown in FIG. 16( c) and FIG. 17( c), four domains that are respectivelyaligned in the left-lower direction, the left-upper direction, theright-lower direction, and the right-upper direction may be formed.

In an exemplary embodiment of the present invention, the light alignmentmethod is used to form four domains having different alignmentdirections in each sub-pixel.

On the other hand, like the exemplary embodiment of the presentinvention, when one pixel includes two sub-pixels, the alignmentdirections of the LC molecules may be determined by the fringe fieldgenerated between the edges of the first sub-pixel electrode 191 a andthe second sub-pixel electrode 191 b and the common electrode 270 nearthe gap 91 between the first sub-pixel electrode 191 a and the secondsub-pixel electrode 191 b, in addition to the alignment directions ofthe light alignment. Therefore, because the alignment directions of theLC molecules determined by light alignment are different from thealignment directions of the LC molecules determined by the fringe fieldgenerated near the gap 91 between the two sub-pixels, texture due to theirregular arrangements of the LC molecules may be generated near the gap91 between the two sub-pixel electrodes.

It was detected that texture was generated in a region where the LCmolecules are declined toward the gap 91, that is, the region in whichthe heads of the arrows are positioned in FIG. 3. Referring to FIG. 3,the position where texture is generated in the present exemplaryembodiment is the left-upper portion and the right-lower portion of thefirst sub-pixel electrode 191 a, and the right-upper portion and theleft-upper portion of the second sub-pixel electrode 191 b.

Accordingly, as shown in FIG. 2, in an exemplary embodiment of thepresent invention, the storage electrode 133, which acts as a shieldingmember, covers the left-upper portion and the right-lower portion of thefirst sub-pixel electrode 191 a and the right-upper portion and theleft-upper portion of the second sub-pixel electrode 191 b and thecircumference of the gap 91 to cover the textures. Accordingly, thetransmittance may be improved and the texture may be prevented frombeing shown as a spot from outside to thereby improve the displaycharacteristics.

In the present exemplary embodiment, the storage electrode, which actsas a shielding member, is disposed on the same layer as the gate line,but it is not limited thereto, and may be disposed on the same layer asthe data line. Further, when the storage electrode functions only as ashielding member, it may not be disposed on the same layer as the gateline or the data line, but may be disposed on the same layer as thelight blocking member 220 of the common electrode panel 200. Also, thelight blocking member 220 may be disposed on the thin film transistorarray panel 100 when the storage electrode is disposed on the same layeras the light blocking member.

Exemplary Embodiment 2

Next, another exemplary embodiment of the present invention will bedescribed in detail with reference to FIG. 6, FIG. 7, FIG. 8, and FIG.9. Descriptions overlapping the previous exemplary embodiment areomitted, and the same constituent elements are indicated by the samereference numerals.

FIG. 6 is a layout view of an LCD according to another exemplaryembodiment of the present invention, and FIG. 7, FIG. 8, and FIG. 9 arelayout views showing a pixel electrode and a gate conductor in the LCDof FIG. 6.

The present exemplary embodiment includes a thin film transistor arraypanel 100 and a common electrode panel 200, and an LC layer 3 formedtherebetween, as in the previously-described exemplary embodiment.

The deposited structures of the thin film transistor array panel 100 andthe common electrode panel 200 are the same as those of thepreviously-described exemplary embodiment, but the present exemplaryembodiment includes a pixel electrode 191 and a storage electrode 133having different shapes from those of the previously-described exemplaryembodiment.

Referring to FIG. 6 and FIG. 7, the pixel electrode 191 according to thepresent exemplary embodiment includes a pair of first and secondsub-pixel electrodes 191 a and 191 b that are divided with a gap 91therebetween.

The upper edge and the lower edge of the first sub-pixel electrode 191 ahave a stair shape. In detail, the left-upper portion of the firstsub-pixel electrode 191 a extends upward and the right-lower portionextends downward. The second sub-pixel electrode 191 b encloses thefirst sub-pixel electrode 191 a.

Referring to FIG. 6 and FIG. 8, the storage electrode 133 has aquadrangular loop shape including an upper portion, a lower portion, aleft portion, and a right portion. The upper portion, the lower portion,the left portion, and the right portion of the storage electrode 133respectively have uniform widths not including the portions extendingupward or downward differently from the previously-described exemplaryembodiment. The upper and lower portions of the storage electrode 133are wider than the left and right portions, and a part of the lowerportion is omitted.

Referring to FIG. 6 and FIG. 9, the storage electrode 133 functions as ashielding member to block light leakage between the first sub-pixelelectrode 191 a and the second sub-pixel electrode 191 b at the gap 91between the first sub-pixel electrode 191 a and the second sub-pixelelectrode 191 b.

Also, the upper portion and the lower portion of the storage electrode133 cover the upper and lower edges of the first sub-pixel electrode 191a having a stair shape so that they function as a shielding member tocover texture generated in this region.

As in the previously-described exemplary embodiment, when the part ofthe LC layer disposed between the first sub-pixel electrode 191 a andthe common electrode 270 is referred to as a first LC layer and the partof the LC layer disposed between the second sub-pixel electrode 191 band the common electrode 270 is referred to as a second LC layer, the LCmolecules 310 of the first LC layer and the second LC layer are alignedin four different directions as shown by the arrows. That is to say,each sub-pixel may include four domains having different alignmentdirections of the LC molecules, such as the left-upper direction, theleft-lower direction, the right-upper direction, and the right-lowerdirection. Such domains may be formed by the light alignment method asdescribed above.

As described above, texture is generated in a region where the directionthat the LC molecules are declined toward the gap 91, that is to say,the left-upper portion and the right-lower portion of the firstsub-pixel electrode 191 a and the right-upper portion and the left-lowerportion of the second sub-pixel electrode 191 b, where the heads of thearrows are positioned as in FIG. 9.

In the present exemplary embodiment, the left-upper portion and theright-lower portion of the first sub-pixel electrode 191 a in which thetexture is generated are extended, and the extended portions are coveredby the storage electrode having a quadrangular loop shape to effectivelycover the texture.

In this structure, it may be easy to control the area ratio of theopenings 234 a, 234 b, 235 a, and 235 b of the color filter 230 so thatasymmetry of viewing angle characteristics may be prevented, thetransmittance may be increased, and display characteristics may beimproved by appropriately covering the texture. Also, the aperture ratiomay be improved as compared with the previously-described exemplaryembodiment.

Exemplary Embodiment 3

Next, another exemplary embodiment of the present invention will bedescribed in detail with reference to FIG. 10, FIG. 11, and FIG. 12.Descriptions overlapping the previous exemplary embodiment are omitted,and the same constituent elements are indicated by the same referencenumerals.

FIG. 10 is a layout view of an LCD according to another exemplaryembodiment of the present invention, FIG. 11 is a schematic diagramshowing a pixel electrode and a shielding member in the LCD of FIG. 10,and FIG. 12 is a cross-sectional view taken along line XII-XII of FIG.10.

The present exemplary embodiment includes a thin film transistor arraypanel 100 and a common electrode panel 200, and an LC layer 3 disposedtherebetween, as in the previously-described exemplary embodiment.

The deposition structures of the thin film transistor array panel 100and the common electrode panel 200 are almost the same as those of theprevious exemplary embodiment, but the color filter 230 is disposed onthe common electrode panel 200 in the present exemplary embodiment.Also, the storage electrode line 131 of the previous exemplaryembodiment is omitted in the present exemplary embodiment, and instead,a shielding member 221 overlapping the gap 91 between the firstsub-pixel electrode 191 a and the second sub-pixel electrode 191 b isincluded in the common electrode panel 200.

First, in the thin film transistor array panel 100, a gate line 121including first and second gate electrodes 124 a and 124 b and a wideend portion 129 is disposed on an insulating substrate 110, and a gateinsulating layer 140 is disposed on the gate line 121.

A semiconductor stripe 151 b including first and second protrusions 154a and 154 b is disposed on the gate insulating layer 140, and an ohmiccontact stripe 161 b, a first ohmic contact island 165 a, and a secondohmic contact island (not shown) are disposed thereon.

A plurality of first and second data lines 171 a and 171 b and aplurality of pairs of first and second drain electrodes 175 a and 175 bare disposed on the ohmic contact stripe and the gate insulating layer140, and a passivation layer 180 is disposed thereon. The passivationlayer 180 has a plurality of contact holes 185 a, 185 b, 182 a, and 182b respectively exposing the first and second drain electrodes 175 a and175 b and the end portions 179 a and 179 b of the first and second datalines 171 a and 171 b, and the passivation layer 180 and the gateinsulating layer 140 have contact holes 181 exposing the end portions129 of the gate lines 121.

A pixel electrode 191 and a plurality of contact assistants 81, 82 a,and 82 b are disposed on the passivation layer 180.

The pixel electrode 191 includes a pair of the first and secondsub-pixel electrodes 191 a and 191 b that are spaced apart with a gap 91therebetween. The upper and lower edges of the first sub-pixel electrode191 a may have a stair shape. In detail, the left-upper portion of thefirst sub-pixel electrode 191 a extends upward and the right-lowerportion extends downward. The second sub-pixel electrode 191 b enclosesthe first sub-pixel electrode 191 a.

Next, the common electrode panel 200 will be described.

A plurality of light blocking members 220 and a plurality of shieldingmembers 221 are disposed on an insulating substrate 210. The lightblocking member 220 includes a straight portion corresponding to thedata line 171 and expansions corresponding to the thin film transistors.Each shielding member 221 has a quadrangular loop shape including anupper portion, a lower portion, a right portion, and a left portion andsufficiently covers the gap between the first sub-pixel electrode 191 aand the second sub-pixel electrode 191 b and the stair-shaped portion ofthe first sub-pixel electrode 191 a.

The left and right portions of the shielding member 221 respectivelyinclude a wide portion 223 and a narrow portion 224. Here, referring toFIG. 11, the width W1 of the wide portion 223 is wider than the width W2of the narrow portion 224 by about 4 to 7 μm. In this way, the wideportion 223 may effectively cover the texture generated in the verticaldirection near the gap 91 between the first pixel electrode 191 a andthe second pixel electrode 191 b.

Color filters 230R and 230G are disposed on the light blocking member220 and the shielding member 221, and an overcoat 250 and a commonelectrode 270 are disposed on the color filters 230R and 230G.

Alignment layers 11 and 21 are disposed on the facing surfaces of thethin film transistor array panel 100 and the common electrode panel 200,respectively, and the alignment layers 11 and 21 have portions that areslanted in various directions by the light alignment method.

An LC layer 3, in which LC molecules 310 are aligned in variousdirections, is disposed between the thin film transistor array panel 100and the common electrode panel 200.

Exemplary Embodiment 4

Next, another exemplary embodiment of the present invention will bedescribed in detail with reference to FIG. 13.

FIG. 13 is a layout view of an LCD according to another exemplaryembodiment of the present invention.

The present exemplary embodiment is almost the same as the ExemplaryEmbodiment 2, but the stair-shaped portion of the upper edge of thefirst sub-pixel electrode 191 a aligns with the vertical center line ofthe second sub-pixel electrode 191 b. In this way, because thestair-shaped portion of the upper edge of the first sub-pixel electrode191 a aligns with the vertical center line of the second sub-pixelelectrode 191 b, the texture generated due to the asymmetry may becovered effectively.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A liquid crystal display, comprising: a first substrate and a secondsubstrate facing each other; a pixel electrode disposed on the firstsubstrate and comprising a first sub-pixel electrode and a secondsub-pixel electrode spaced apart from the first sub-pixel electrode by agap; a common electrode disposed on the second substrate; a shieldingmember disposed on the first substrate or the second substrate andoverlapping the gap between the first sub-pixel electrode and the secondsub-pixel electrode; an alignment layer disposed on at least one of thepixel electrode and the common electrode; and a liquid crystal layerdisposed between the first substrate and the second substrate.
 2. Theliquid crystal display of claim 1, wherein the liquid crystal layercomprises: a first liquid crystal layer disposed between the firstsub-pixel electrode and the common electrode; and a second liquidcrystal layer disposed between the second sub-pixel electrode and thecommon electrode, wherein the first liquid crystal layer and the secondliquid crystal layer comprise a plurality of domains having differentalignment directions from each other.
 3. The liquid crystal display ofclaim 2, wherein the shielding member comprises: a first portionoverlapping the gap, and a second portion extended from the firstportion to overlap the first sub-pixel electrode or the second sub-pixelelectrode.
 4. The liquid crystal display of claim 3, wherein the firstsub-pixel electrode is a quadrangle, and the second sub-pixel electrodeencloses the first sub-pixel electrode.
 5. The liquid crystal display ofclaim 2, wherein the first sub-pixel electrode comprises a stair-shapedportion, and the second sub-pixel electrode encloses the first sub-pixelelectrode.
 6. The liquid crystal display of claim 5, wherein aquadrangular loop shaped portion of the shielding member covers thestair-shaped portion of the first sub-pixel electrode.
 7. The liquidcrystal display of claim 6, wherein the shielding member has a shape ofan open quadrangular loop.
 8. The liquid crystal display of claim 6,wherein the quadrangular loop comprises an upper portion, a lowerportion, a left portion, and a right portion, and the upper portion andthe lower portion are wider than the left portion and the right portion.9. The liquid crystal display of claim 6, wherein the quadrangular loopcomprises an upper portion, a lower portion, a left portion, and a rightportion, and at least one of the left portion and the right portion ofthe quadrangular loop comprises a first portion and a second portionthat is wider than the first portion.
 10. The liquid crystal display ofclaim 9, wherein the second portion is 4 to 7 μm wider than the firstportion.
 11. The liquid crystal display of claim 2, further comprising:a first thin film transistor connected to the first sub-pixel electrode;a second thin film transistor connected to the second sub-pixelelectrode; a gate line connected to the first thin film transistor andthe second thin film transistor; and a data line crossing the gate line,wherein the shielding member is disposed on the same layer as the gateline or the data line.
 12. The liquid crystal display of claim 2,further comprising: a light blocking member disposed on at least one ofthe first substrate and the second substrate, wherein the shieldingmember is disposed on the same layer as the light blocking member. 13.The liquid crystal display of claim 2, wherein the plurality of domainsis formed by irradiating light onto the alignment layer in differentdirections.
 14. The liquid crystal display of claim 13, wherein thealignment layer comprises a first alignment layer disposed on the firstsubstrate and a second alignment layer disposed on the second substrate;the first alignment layer comprises a first portion irradiated in afirst direction and a second portion irradiated in a second directionopposite to the first direction; and the second alignment layercomprises a third portion irradiated in a third direction crossing thefirst direction and a fourth portion irradiated in a fourth directionopposite to the third direction.
 15. A liquid crystal display,comprising: a pixel electrode comprising a first sub-pixel electrode anda second sub-pixel electrode; a common electrode facing the pixelelectrode; a first liquid crystal layer disposed between the firstsub-pixel electrode and the common electrode, the first liquid crystallayer comprising a plurality of domains where liquid crystal moleculesare aligned in a left-upper direction, a left-lower direction, aright-upper direction, and a right-lower direction, respectively; asecond liquid crystal layer disposed between the second sub-pixelelectrode and the common electrode, the second liquid crystal layercomprising a plurality of domains where liquid crystal molecules arealigned in the left-upper direction, the left-lower direction, theright-upper direction, and the right-lower direction, respectively; anda shielding member disposed under the pixel electrode or under thecommon electrode and overlapping a gap between the first sub-pixelelectrode and the second sub-pixel electrode.
 16. The liquid crystaldisplay of claim 15, wherein the shielding member comprises: a firstportion overlapping the gap, and a second portion extending upward ordownward from the first portion to overlap the first sub-pixel electrodeor the second sub-pixel electrode.
 17. The liquid crystal display ofclaim 16, wherein the first sub-pixel electrode is a quadrangle; and thesecond sub-pixel electrode encloses the first sub-pixel electrode. 18.The liquid crystal display of claim 15, wherein the first sub-pixelelectrode comprises a stair-shaped portion; and the second sub-pixelelectrode encloses the first sub-pixel electrode.
 19. The liquid crystaldisplay of claim 18, wherein the shielding member has a quadrangularloop shape covering the stair-shaped portion of the first sub-pixelelectrode.
 20. The liquid crystal display of claim 15, furthercomprising: an alignment layer disposed on at least one of the pixelelectrode and the common electrode, wherein the plurality of domains ofthe first liquid crystal layer and the second liquid crystal layer areformed by irradiating light onto the alignment layer in differentdirections.